Pneumatically assisted conformal tool for an ophthalmic lens finer/polisher

Abstract

A conformal tool for fining/polishing ophthalmic lenses has a rigid base, a substantially air impervious elastic membrane and a bladder conformable to a surface of the lens to be fined/polished. The perimeters of the base, the membrane and the bladder are contiguously clamped to provide a pneumatically discrete chamber between the base and the membrane and a chamber containing conformable filler such as sand between the membrane and the bladder. The pneumatically discrete and filler containing chambers together have a substantially fixed volume. The clamping provides a passage into the pneumatically discrete chamber so that air under pressure, when admitted into the pneumatically discrete chamber, stretches the membrane to increase the pneumatically discrete chamber volume and decrease the filler containing chamber volume. As air pressure is increased, the air separates the membrane from the base to build an air cushion therebetween as the conformable filler chamber volume decreases.

What is claimed is: 
     
       1. A conformal tool for fining/polishing ophthalmic lenses comprising: an rigid circular base having a arcuate front surface with a flattened central portion extending from a peripheral flange;   a spacer ring of depth less than a depth of said arcuate front surface seated on said flange;   a substantially circular air impervious elastic membrane extending across said flattened portion of said arcuate surface;   a first clamping ring securing a perimeter of said membrane against said spacer ring with said membrane stretched across a portion of said arcuate surface extending beyond said spacer ring;   a substantially hemispherical bladder forming an outer surface conformable to a surface of the lens to be fined/polished;   a second clamping ring securing a perimeter of said bladder against said first clamping ring; and   means contiguously fixing perimeters of said base, said spacer ring, said membrane, said first clamping ring, said bladder and said second clamping ring to provide a pneumatically discrete chamber between said base, said spacer ring and said membrane and a chamber containing conformable filler between said membrane, said first clamping ring and said bladder, said pneumatically discrete and filler containing chambers together having a substantially fixed volume;   said spacing ring having a passage therethrough into said pneumatically discrete chamber whereby air under pressure let into said pneumatically discrete chamber stretches said membrane to increase said pneumatically discrete chamber volume and decrease said filler containing chamber volume.   
     
     
       2. A tool according to claim 1, said conformable filler being sand. 
     
     
       3. A tool according to claim 1, said base having a rear portion adapted for connection to a chuck of a fining/polishing machine. 
     
     
       4. A tool according to claim 1, said first clamping ring having a flange extending from an inner diameter thereof into said bladder. 
     
     
       5. A tool according to claim 4, said bladder having a flange extending about a hemispherical edge thereof and between said first and second clamping rings. 
     
     
       6. A tool according to claim 5, said first clamping ring having an annular seat along an inner diameter thereof for receiving said bladder flange therein. 
     
     
       7. A tool according to claim 1, said fixing means comprising a plurality of holes spaced about and aligned through perimeters of said base, said spacer ring, said membrane and said first and second clamping rings, said second clamping ring holes being threaded, and a plurality of bolts extending through said holes and having ends threadedly engaged in said second clamping ring holes.